Major Parts of Oil Filters
The following are the internal components of the oil filter:
Tapping Plate:
The tap plate is the inlet and outlet point on the oil filter. It has small holes around the edges to allow oil to flow freely into the filter container. The threaded hole in the center is where the oil flows out, and it faces the engine.
Antidrainback Valve
The oil filter section is a rubber valve with a valve disc which prevents oil from flowing back to the filter when the engine is not running. The filter needs to do this because it is located between the middle or bottom of the engine.
Filter Medium:
Porous filter media include microscopic cellulose fibers and synthetic fibers such as polyester and glass. It helps to improve filtration durability and efficiency. It is also impregnated with resin to provide hardness and strength. High performance filters use more synthetic fiber designs.
Pleats:
The folded filter media produce a larger total surface area. The number of folds depends on the thickness of the medium.
Center Steel Tube:
The oil filter component provides the structure for the filter and allows the filtered oil to return to the engine. The number, size, and location of the holes will ensure effective oil flow without restriction.
Relief Valve:
As the oil may be too rich to filter during cold start, it is necessary to prevent the engine from starvation. The oil filter is designed with a relief valve that opens when sufficient pressure is generated to force the calibration spring downward. This allows unfiltered oil to enter the center tube through the top.
End Disc:
The end plate is made of fiber or metal to prevent unfiltered oil from leaking into the central pipe. The end plate is bonded to each end of the filter medium.
Retainer:
The retainer is a metal that acts as a leaf spring. It tightly sticks the filter medium and end plate on the tap plate.
The following is a complete schematic of the oil filter:
